This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Expression of enzymes involved in glycoprotein biosynthesis for structural analysis by NMR and X-ray crystallography is being optimized in mammalian (HEK293) cells. High yield expression was previously accomplished in Pichia pastoris and 15N- 13C-, and 2H-labeling methods were achieved at low levels. Expression of several recombinant enzymes in HEK293 cells has also been accomplished and several of the proteins are entering screening for crystallization conditions.